DAVID CAMERON said no nation has a “bigger heart” in a passionate defence of the UK after Russia reportedly dismissed us as an insignificant “small island”.

President Vladimir Putin’s official spokesman ­Dmitry Peskov allegedly unleashed the astonishing insult in a briefing to Russian journalists.

Mr Peskov is understood to have said: “Britain is a small island nobody pays any attention to, apart from the Russian ­oligarchs who bought up Chelsea.”

In response to the alleged comments, which signal the bitter division between the UK and Russia over Syria, the Prime Minister made an impassioned speech in which he championed the UK's achievements.

He said to reporters: "I've been told that the Russians absolutely deny making the remark, and certainly no one's made it to me.

"But let me be clear - Britain may be a small island, but I would challenge anyone to find a country with a prouder history, a bigger heart or greater resilience.

"Britain is an island that has helped to clear the European continent of fascism and was resolute in doing that throughout the Second World War.

"Britain is an island that helped to abolish slavery, that has invented most of the things worth inventing, including every sport currently played around the world, that still today is responsible for art, literature and music that delights the entire world.

"We are very proud of everything we do as a small island - a small island that has the sixth-largest economy, the fourth best-funded military, some of the most effective diplomats, the proudest history, one of the best records for art and literature and contribution to philosophy and world civilisation."

The Prime Minister is currently at the G20 Summit

Britain may be a small island, but I would challenge anyone to find a country with a prouder history, a bigger heart or greater resilience

David Cameron

He added: "For the people who live in Northern Ireland, I should say we are not just an island we are a collection of islands. I don't want anyone in Shetland or Orkney to feel left out by this."

Meanwhile Downing Street has firmly disowned Tory backbencher Henry Smith after he took to Twitter to describe the Russian president as a "t****r".

The Crawley MP said the insult was based on more than the current stand-off over whether to take action over Syria.

"There is his abuse of human rights against the gay community in his own country, there is the abuse of human rights in Syria where the way he is helping and prolonging that civil war there is appalling," he told the Press Association.

"On Twitter in a slight fit of pique I might refer to him as a t****r. But in other forums, such as the House of Commons, I would accuse him of being an absurd character."

He added: "I may not use that colloquial language in other forums, but frankly it is still how I feel."

The Prime Minister's spokesman said it was "no secret" that there was disagreement on the Syria issue, but insisted the Government took a "robust but constructive approach" to Russia.

Asked if the Prime Minister disapproved of Mr Smith's comment, the spokesman said: "I think that we need a robust but constructive approach. Anything else, well, I just think that's clearly not how the Government goes about its relations with Russia."

The spokesman said the need for constructive engagement with Russia "should be reflected in the language people use".

The comments came as Mr Cameron ruled out any prospect of an international agreement over Syria at the G20 summit in St Petersburg, saying that Mr Putin remains "miles away" from the truth of Bashar al-Assad's use of chemical weapons on his own people.